info on fender twin reverb, please!

[lucid]

why is it called a TWIN reverb? it only has one reverb knob...

what are the little tubes for?

and what kind of tubes are needed to replace the old ones... i think that they are still the original tubes from the 60's...

 

[Lt. Bob]

What are the tubes for?

you're kdding right?

 

[Fangar]

I think he has smoked some of the same ironing board cloth that Sonsuman has been smoking.

Fangar

 

[dragonworks]

You dont need the little tubes, there only there in case the big ones break down. You can take them out and put them in a safe place. Its called a twin
because of the reverb, kind of like an echo thing, reflecting itself, like a twin
of itself. Thats why it only has one knob because thats what makes it reverb and echo itself making it a twin.

 

[Track Rat]

You guys are brutal

 

[NYMorningstar]

My mother had twins once then went and had her tubes tied!

 

[philboyd studge]

Because it has two 12" speakers as opposed to a single 12" in a delux, it was called a twin.

 

[joro]

hahahahahahaha

You need glass tubes....silly

 

[lucid]

thanks for the help; from those who actually helped...

and yes i meant the little tubes as opposed to the big ones...

so what do the 'smaller' tubes do?

and anyone know which ones to replace them with?
does changing of tubes affect the sound in any way?

thanks

-tube amp newbie-

 

[dragonworks]

http://www.kbapps.com/schematics/tubeamps/fender/index.html
Here is a link to schematics for fender amps, you should be able to find yours here. The small tubes are preamp tubes and driver tubes for the reverb etc.
It is called a twin because of the 2 12 inch speakers allready mentioned in a previous reply. The tubes will most probably be 7025, 12ax7a, 12au7s, check the schematics to see which tubes they are. If the amp is old enough there will be a rectifier tube for the power supply instead of diodes, the only rectifier tube I know off hand is a 5u4gb but there are many more.
I hope this helps
PS we thought you were kidding.

 

[Clive Hugh]

Assuming you are serious and I'll give you the benefit of the doubt. The small tubes are for your preamp circuit, this is where the sound is shaped and gets it's sound , character or whatever you call it. The large tubes are your power tubes and provide the amplification.
They all affect your sound, before you replace think carefully, you might totally fuck up.
Unless they are are stuffed there is really no need to change, HOWEVER if you are a tube fiddler as opposed to a knob fiddler check out some of the tube suppliers such as Mesa Boogie, you can really change the sound from harsh glassy to soooo sweet. Look them up online and they will answer most queries.
Good luck, if it is original, don't trash your old tubes, hang on to them they are a good point if you want to sell.

 

[Fangar]

Dude?

Hey Lucid,

Sorry about that. I could have swore you were pullin a silly one on us. Listen to what the guys say about research and assistance with tube replacement. It is also gonna be kinda expensive for the whole lot of them.

Fangar

 

[dragonworks]

The price all depends. Where I am there is an electronics store that has a large inventory left over from the old days and they sell them pretty cheap just to get rid of them. You can also try your salvage yards or salvage wharehouses, they buy tubes from places in large lots and sell them pretty cheap. There is a place here that does that, can probably by a whole box full for ten bucks but its pot luck and most of them are old tv tubes.

 

[Fangar]

The price all depends. Where I am there is an electronics store that has a large inventory left over from the old days and they sell them pretty cheap just to get rid of them. You can also try your salvage yards or salvage wharehouses, they buy tubes from places in large lots and sell them pretty cheap. There is a place here that does that, can probably by a whole box full for ten bucks but its pot luck and most of them are old tv tubes.

I agree this is a possibility, but an amp re-tubed with all new tubes as opposed to hit or miss, unmatched tubes will definately take on different tonal qualities.

Fangar

 

[Lt. Bob]

Sorry Lucid for not helping right off

In a Twin, the small tubes will be 12ax7's and the big tubes will be 6L6's. The only exception would be the rectifier tube (if it has one) and sometimes there is a different tube for the reverb. Preamp tubes (the small ones) usually last a long time so they're probably ok unless they're very old. The power tubes (big ones) can need replacing as often as yearly if you use them a lot. If there is strong, unusual distortion or a ringing--almost like feedback; that would be a power tube. It's usually best to replace them both. Places like musician's friend have them for not too much money. Maybe $20-$25 for the power tubes and about $15 for the preamp tubes. I think when you get it going you'll see why a lot of players prefer tubes. Good luck.

 

[dragonworks]

If you refer to the link provided above you will find that there are many tube configurations for the Twin depending on the model number. Some use 7025 and some use 12ax7s for the preamps etc.

 

[Lt. Bob]

OK I stand corrected. I would've sworn it was all 12ax7's. Imagine my shock when my amp launched itself through the ceiling.

 

[lucid]

thanks for all the help guys. this isn't my amp (but i wish it was!). but, the small tubes are not there! yes, sometimes it distorts (not the pleasing kind) and it is very moody with its treble. power tubes then eh?

how can i tell whether or not it usues a rectifier tube or diode?

cheers

-nick

 

[Lt. Bob]

Go to the link Dragon gave and count tubes maybe. I think the ones with rectifier tubes have a different number of tubes. Also have you looked closely at the inside walls of the cabinet? Usually they will have a tube chart stuck on there. Also if the little tubes aren't even there, I'm not sure how it could be working at all. Those are the pre-amp tubes in the same sense that a mixer is a pre-amp for a power amp. If they aren't there then there wouldn't be any signal for the power amp to work with. So if they are missing...they would be what I'd worry about finding first. Like I said 'though, I don't see how it could be working without pre-amp tubes.

 

[Clive Hugh]

If you get round to replacing the power tubes make sure you get it biased, on the newer Fenders it is relatively easy but on the old ones it was a pain, but it will increase your tube life.

Clive